1. Field of the Invention
The present invention relates to a housing for enclosing a measuring apparatus for a recording apparatus such as a magnetic head, a recording medium of a hard disk drive unit, or the like, and in particular, to a housing for enclosing a measuring apparatus, provided with air blowing means including a high efficiency particulate air filter.
2. Description of the Related Art
In a conventional measuring apparatus for use in a recording apparatus such as a hard disk drive unit, a recording medium such as a hard disk or the like is covered with a cover, and the cover is opened in only a small area for a measuring part or the whole apparatus is covered with a cover, in order to reduce the influence of variation in ambient temperature and winds.
When the recording medium is covered with the cover which is opened in only the small area for the measuring part, the cover located around the recording medium imposes limits the measuring range of the recording medium. Moreover, the cover cannot completely keep out of external temperatures and winds having unstable directions, and this leads to variation in results of measurement.
Further, in the case where the whole apparatus is covered with the cover, there is the following problem. The heat generated by a spindle, a motor or the like causes a difference in temperature between an internal area within the cover of the measuring apparatus, and an outer area thereof, and thus, the temperature in the internal area within the cover thereof changes due to opening and closing of a door upon replacement of magnetic heads, then wind is generated, this leads to variation in the results of the measurement.
Recently, hard disk manufacturers have increased a recording density of the recording medium accompanying with increase in a recording capacity of the hard disk drive unit. Accompanying with this, it has been necessary to provide a glass-recording medium having a high surface precision in order to keep a flying height of a magnetic head stable. It is a known fact that the glass-recording medium is easy to break as compared with an aluminum recording medium and that flying broken glass is dangerous. The cover opened in only the small area for the measuring part is not used for the measurement by means of the glass-recording medium in consideration of safety. When the whole apparatus is covered with the cover, the spindle is stopped at the time of the replacement of the magnetic head in order to improve safety. When the spindle is stopped, heat generated by the acceleration of the spindle causes a change in temperature of the recording medium and its surroundings and thus results in a deterioration in the precision.
It is an essential object of the present invention to provide a housing for enclosing a measuring apparatus for a recording apparatus, which is capable of maintaining the environment of temperature and air flow around a recording medium and a magnetic head which are objects to be measured by the measuring apparatus for the recording apparatus such as a hard disk drive unit, thereby preventing variation in results of measurement.
In order to achieve the aforementioned objective, according to one aspect of the present invention, there is provided a housing for enclosing a measuring apparatus for a recording medium and a recording apparatus for recording a signal on the recording medium, comprising:
air blowing means including a high efficiency particulate air filter, the air blowing means blowing air onto the recording medium and the recording apparatus under measurement, through the high efficiency particulate air filter, at a substantially constant air temperature and at a substantially constant air flow rate.
The above-mentioned housing preferably further comprises an automatic door located at a position other than an air protection area which includes positions of the recording medium under measurement by the recording apparatus and the recording apparatus and includes a predetermined surrounding area, the automatic door shielding the other area from the air protection area in the housing for enclosing measuring apparatus under no measurement.
Further, the above-mentioned housing preferably further comprises an outer door adapted to open and close only when the automatic door shields the other area from the air protection area.
Furthermore, the above-mentioned housing preferably further comprises moving means for moving the recording medium and the recording apparatus to be measured, to the air protection area when the automatic door is open.
Furthermore, in the above-mentioned housing, the recording medium is preferably a hard disk recording medium, and the recording apparatus comprises a magnetic head.